Michael
Becker
submits:
Next month [November] marks Pancreatic Cancer Awareness Month.
Visibility for the disease is already on the rise due to recent
celebrity victims, including Apple's Steve Jobs and Hollywood actor
Patrick Swayze.
According to the
American Cancer
Society
, pancreatic cancer is a devastating disease with the worst
mortality rate and an overall 5-year survival rate lower than 5%.
Although accounting for only 3% of all cancers, this disease is the
fourth leading cause of death and represents 6% of all cancer
related deaths in the United States.
The disease remains one of the most difficult to treat due to
late initial diagnosis and extreme resistance to treatment. For
example, about 50% of patients have locally advanced disease at the
time of diagnosis, indicating that the cancer has grown beyond the
confines of the pancreas to invade surrounding vital structures,
and in 40% of patients the tumor has spread to distant sites, such
as the liver and lungs [metastatic stage]. Case in point: Patrick
Swayze was diagnosed with stage IV pancreatic cancer that had
already spread to the liver in March 2008 and lost his battle with
the disease in September 2009 at the age of 57.
The majority of pancreatic tumors [95%] are adenocarcinomas that
mainly develop from exocrine cells in the tissues of the pancreas.
They are characterized by an aggressive behavior with a fast
progression rate that makes them highly metastatic. Neuroendocrine
tumors [NET] of the pancreas [islet cell tumors] are much less
common [1-2%] than exocrine pancreatic tumors and are considered
less deadly. For example, Steve Jobs, co-founder and chief
executive of Apple Inc. (
AAPL
), was diagnosed with this rare, slow-growing pancreatic tumor in
2004.
In terms of treatment, surgical removal of the tumor represents
the best option for pancreatic cancer patients without invasion
into surrounding organs or distant metastasis. Unfortunately, only
15-20% of all patients are candidates for potentially curative
surgery. Depending on the tumor localization,
pancreaticoduodenectomy, distal or total pancreatectomy can be
performed. However, even with an optimal curative surgery,
metastases often occur. Median survival time without evidence of
recurrent disease is 21.2 months after resection.
For locally advanced or metastatic disease, treatment is still
palliative rather than curative, and chemotherapy remains the only
option. Since its approval in 1997, Eli Lilly's (
LLY
) Gemzar® [gemcitabine] is the current standard first-line
treatment in the U.S. It has been shown to improve the median time
to disease progression and overall survival [OS].
Just like lupus, sepsis, and several others, pancreatic cancer
has been referenced as one of those challenging diseases where good
drugs [and companies…] go to die. Since 2005, nine late-stage
clinical trials have been performed to improve the efficacy of
gemcitabine with little success in terms of improving survival
outcomes [see Table 1]. Such failures resulted in at least two
companies filing for bankruptcy [both Aphton Corp and Therion
Biologics in 2006]. In fact, the only combination approved by the
U.S. Food and Drug Administration [FDA] is gemcitabine plus
Astellas Pharma's Tarceva® [erlotinib], which increased the median
OS from 6.0 to 6.4 months.
Table 1. Prominent Late-stage Pancreatic Product
Failures
|
Company
|
Product
|
Class
|
Stage
|
Year
|
| GenVec, Inc. (
GNVC
) |
TNFerade |
Gene therapy |
Phase 3 |
2010 |
| Pfizer, Inc. (
PFE
) |
Axitinib |
Kinase inhibitor |
Phase 3 |
2009 |
| Therion Biologics |
PANVAC-VF |
Immunotherapy |
Phase 3 |
2006 |
| SciClone Pharmaceuticals, Inc. (
SCLN
) |
RP101 |
Chemotherapy |
Phase 2 |
2009 |
| Regeneron Pharmaceuticals, Inc. (
REGN
)/Sanofi-Aventis (
SNY
) |
Aflibercept |
Fusion protein |
Phase 3 |
2009 |
| ImClone/Eli Lilly & Co. (
LLY
) |
Erbitux® [cetixuimab] |
Monoclonal antibody |
Phase 3 |
2007 |
| Roche Holding AG (RHHBY.PK) |
Avastin® [bevacizumab] |
Monoclonal antibody |
Phase 3 |
2007 |
| Aphton Corp |
Insergia |
Immunotherapy |
Phase 3 |
2005 |
| Supergen, Inc. (
SUPG
) |
Orathecin |
Chemotherapy |
Phase 3 |
2005 |
Despite past failures, drug developers continue to explore new
options for treating pancreatic cancer and more than a dozen new
molecular entities are currently being evaluated in clinical trials
[see Table 2]. Several programs have recently demonstrated
impressive results in Phase 2 studies and are now enrolling
patients in pivotal trials. While a comprehensive review of
investigational pancreatic cancer therapies is beyond the scope of
this article, we briefly review some of the more promising
pancreatic treatments currently in clinical development:
Celgene Corporation
Historically known more for its franchise in treating blood
cancers, Celgene moved into the realm of solid tumors through its
recent acquisition of Abraxis BioScience, Inc. As a result, Celgene
is now developing Abraxane® [paclitaxel protein-bound particles for
injectable suspension] for the treatment of pancreatic cancer.
Updated overall survival findings from a phase I/II study of
Abraxane given in combination with gemcitabine demonstrated
increased survival of the first-line treatment of patients with
advanced pancreatic cancer.
In 44 patients treated at the recommended dose of 125 mg/m2
Abraxane plus gemcitabine [1000 mg/m2], the median OS time was 12.2
months, an impressive doubling of survival compared to historical
control of gemcitabine administered alone. The findings were
discussed at the 101st Annual Meeting of the American Association
for Cancer Research [AACR] in 2010. The combination of Abraxane and
gemcitabine is now the treatment arm of a randomized Phase 3
clinical trial that is currently enrolling patients
[ClinicalTrials.gov identifier NCT00844649].
Novartis AG
In June 2010, at the 12th World Congress on Gastrointestinal
Cancer, Novartis reported that its RADIANT-3 Phase 3 study of
Afinitor® (everolimus), plus best supportive care met its primary
endpoint, showing that the drug more than doubled median
progression-free survival [PFS], or time without tumor growth, from
4.6 to 11.0 months when compared with placebo in patients with
advanced pancreatic NET.
More recently, Novartis presented data from a second Phase 3
study called RADIANT-2 at the 35th European Society for Medical
Oncology [ESMO] Congress. The study, which evaluated Afinitor® in
combination with Sandostatin® LAR Depot (octreotide acetate for
injectable suspension), demonstrated that everolimus plus
octreotide LAR provided a clinically meaningful extension in the
median time without tumor growth from 11.3 to 16.4 months when
compared with placebo plus octreotide LAR. However, the study did
not meet its primary endpoint of PFS based on central radiologic
review of the data (p=0.026 versus p=0.024 predefined). According
to the company, results from the two RADIANT trials will form the
basis for regulatory filings later in 2010.
Amgen, Inc.
Amgen is developing AMG 479, an investigational fully human
monoclonal antibody that targets type 1 insulin-like growth factor
receptor [IGF-1R], which plays an important role in the regulation
of cell growth and survival. At the 2010 American Society of
Clinical Oncology [ASCO] Annual Meeting, Amgen announced results
from a Phase 2 study demonstrating that the addition of AMG 479 to
gemcitabine resulted in an overall survival rate at six months of
57% versus 50% with gemcitabine alone and 39% versus 23% at 12
months. Median overall survival was 8.7 months versus 5.9 months in
the gemcitabine arm. AMG 479 is moving into a Phase 3 study for
metastatic pancreatic cancer.
Threshold Pharmaceuticals, Inc.
At the 2010 ASCO Annual Meeting, Threshold Pharmaceuticals
presented results with its hypoxia-activated prodrug, TH-302, in
combination with gemcitabine in thirty-four patients with advanced
or metastatic pancreatic cancer that had at least one evaluable
post-treatment tumor assessment. One patient [3%] demonstrated a
complete response as measured by RECIST [Response Evaluation
Criteria In Solid Tumors] and 8 patients [24%] had a partial
response. Of the 34 assessed patients, 28 had elevated carbohydrate
antigen CA19-9 levels at baseline and 17 of 28 [61%] had a CA19-9
reduction of greater than 50%. This is important, as a greater than
20% decrease in levels of this tumor-associated antigen has been
shown to correlate with improved overall survival. The biomarker
CA19-9 has been shown to be highly specific and sensitive for
pancreatic cancer and approximately three-quarters of all
pancreatic cancer patients have elevated baseline serum CA19-9
level at baseline.
Neogenix Oncology, Inc. (private)
Neogenix Oncology is develping ensituximab, a novel, chimeric
monoclonal antibody intended for the treatment of advanced
pancreatic and colorectal cancer. Pre-clinical studies have
demonstrated that NPC-1C specifically targets pancreatic and
colorectal cancer sparing healthy tissue. In 2010, the company
initiated a multi-center Phase 1 trial in patients with late stage
pancreatic or colorectal cancer being conducted at Johns Hopkins
University Hospital, Duke University Medical Center, and North
Shore University Hospital. Neogenix is also exploring the
diagnostic and prognostic utility of ensituximab using a new serum
ELISA test in a prospective study. Preliminary results demonstrate
that the biomarker test can differentiate between blood serum of
healthy donors and that of patients with colorectal or pancreatic
cancer. In addition, the results of the biomarker test indicate
superior sensitivity as compared to commercially available CEA and
CA19-9 assays.
Table 2. Select Pancreatic Products in Active Clinical
Development*
|
Company
|
Product
|
Class
|
Stage
|
| Celgene (
CELG
)/Abraxis |
Abraxane |
Chemotherapy |
Phase 3 |
| Novartis AG (
NVS
) |
Afinitor® (everolimus) |
Signal transduction inhibitor |
Phase 3 |
| Amgen (
AMGN
) |
AMG 479 |
Monoclonal antibody |
Phase 2 |
| Threshold Pharmaceuticals (
THLD
) |
TH-302 |
Chemotherapy |
Phase 2 |
| Oncolytics Biotech (
ONCY
) |
Reolysin® |
Reovirus |
Phase 2 |
| Celgene (
CELG
)/GlobeImmune (private) |
GI-4000 |
Targeted molecular immunotherapy |
Phase 2 |
| Pharmacyclics (
PCYC
) |
PCI-27483 |
Signal transduction inhibitor |
Phase 2 |
| BioSante Pharmaceuticals (
BPAX
) |
GVAX Pancreas Vaccine |
Immunotherapy |
Phase 2 |
| Novartis AG (
NVS
) and Bayer Schering Pharma AG (BAYRY.PK) |
Vatalanib (PTK787/ZK-222584) |
Kinase inhibitor |
Phase 1/2 |
| Infinity Pharma (
INFI
) |
IPI-926 |
Signal transduction inhibitor |
Phase 1b/2 |
| Immunomedics (
IMMU
) |
Clivatuzumab tetraxetan, 90Y-hPAM4 |
Monoclonal antibody - radiolabeled |
Phase 1b |
| Neogenix Oncology (private) |
Ensituximab, NPC-1C |
Monoclonal antibody |
Phase 1 |
| Seattle Genetics (
SGEN
)/Astellas Pharma (ALPMY.PK) |
ASG-5ME |
Monoclonal antibody - drug conjugate |
Phase 1 |
| Celldex Therapeutics (
CLDX
) |
CDX-1307 |
Monoclonal antibody |
Phase 1 |
* Based on ClinicalTrials.gov
Conclusion
In contrast to the prominent late-stage failures over the past
five years, several drugs have recently shown promise for the
treatment of pancreatic cancer. Going forward, early detection
using biomarkers, more effective treatments, and novel drug targets
could provide new hope for the treatment of this deadly disease.
Disclosure:
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